In a coating device (11) for coating a solar cell (12) with metal, for example copper, in a coating bath (16), light sources (20) are provided. By virtue of the light (22) from said light sources, the solar cells (12) become electrically conductive and can be coated with copper from the coating bath (16) when a voltage is applied. The light (22) from the light sources (20), which can advantageously be LEDs (21) has a colour or light wavelength which is chosen precisely such that it radiates as well as possible through the coating bath (16) or has minimum losses. In the case of copper, the light (22) is blue owing to the blue coating bath (16).